JPS59215913A - Resonator - Google Patents

Abstract

PURPOSE:To elevate the damping effect of a resonator by connecting ducts such as the suction air duct, etc. of an internal-combustion engine to a resonator comprising a totally enclosed space via plural-number of tubular members and making the resonance frequency variable by changing the sectional area of the opening of these tubular members. CONSTITUTION:Two tubular members 15,16 respectively with openings in different diameters are provided in parallel in the route of a suction duct 13 connected to the upper end of an air cleaner 11 via. a suction pipe 12 and the other ends of respective members 15,16 are connected to a resonator 19 having a resonance chamber 8. A freely rotating shutter plate 17, for connecting at least either one of the tubular members 15, 16 to the inside of the resonance chamber 8 is provided at the end of the openings of these tubular members 15,16 to the resonance chamber 18, and this shutter plate is rotated as controlled by an actuator 20 as synchronized with the rotation of the engine. The shutter plate 17 is formed with drilled No.1 through No.3 connecting holes 17a- 17c, capable of engaging with respective tubular members 15,16, and the diameter D1 of the holes 17a, 17b is made same as the inner diameter of the tubular member 15 and the diameter D2 of the hole 17c is made same as the inner diameter of the tubular member 16.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resonator that varies a resonant frequency in synchronization with the rotational speed of an internal combustion engine, and is effective for use, for example, as an intake noise muffling device in an intake system of an internal combustion engine.

A conventional resonator was constructed as shown in FIG.

(1) That is, the conventional resonator consists of a tubular member 15' that is installed in the middle of the intake duct 13 and communicates with the inner suction passage 14 of the intake duct 13, and a resonance chamber in which the end surface of this tubular member 15' is open. It was configured. The resonant frequency fP of this resonator 19' is fp-C/2π·7πn-/JV
1(−0,8D...(11). Here, D
is the inner diameter of the communicating tubular member 15', and l is the inner diameter of the communicating tubular member 15'.
The length is the internal volume of the resonant chamber 18'. Therefore, in the conventional resonator, the resonant frequency fP is not uniformly determined due to its structure, and a damping effect is obtained only at that specific resonant frequency fP.

In contrast to conventional resonators that can obtain only a specific single resonance frequency, the present invention makes the resonance frequency variable by variably controlling the opening cross-sectional area of the communicating tubular member represented by the formula ( ]),
This is intended to widen the frequency range in which the damping effect can be obtained.

Next, an embodiment in which the present invention is used as an intake noise muffling device in an internal combustion engine intake system will be described with reference to FIG.

(2) In Fig. 2, 1 is a cylinder in which a piston 2 is slidably fitted, and a part of it is covered with a cylinder head 3.
Further, the cylinder head 3 is formed with an intake valve 4, an exhaust valve 57, an intake port 6 which is periodically opened and closed, and an exhaust lower. The exhaust lower communicates with an exhaust pipe via a tJ exhaust passage 8, and this exhaust pipe is provided with a muffler (not shown) for muffling exhaust noise.

On the other hand, the intake port 6 is connected to an intake passage 9 and a carburetor 10 (
In the case of a diesel vehicle, the air cleaner 11 is connected to an air cleaner 11 for purifying the intake air. A suction pipe 12 is attached to the upstream end of the air cleaner 11. An intake duct 13 is connected to the tip of the suction pipe 12, and a tip opening 13a of the intake duct 13 is open to the atmosphere.

In the middle of this intake pipe 12 or intake duct 13 (intake duct 13 in this embodiment), this intake duct 13
A first tubular member 15 and a second tubular member 16 having different opening diameters and communicating with the suction passage 14 inside are provided in parallel (3), and a resonance chamber is provided at the other end of the first and second tubular members 15 and 1.6. A resonator 19 having 18 is provided. 1. The length of the second tubular member 15.16 is β, the inner diameter of the first tubular member 15 is DI, the inner diameter of the second tubular member 16 is D2, r)]>D2
shall be. Furthermore, in order to obtain multiple resonant frequencies, the first
, the opening/closing plate 17 for communicating at least one of the two tubular members 15 and 16 with the resonance chamber 18 is rotatably slidable relative to the open end of the first and second tubular members 15 and 16 to the resonance chamber 18. and the shaft 2 is connected to the actuator 2° fixed on the side opposite the tubular member 15, 16 of the resonator 19.
It is fixed via 1. The intake duct 13 is a resin blow molded product, and the tubular members 15 and 16 of this embodiment are
, the opening/closing plate 17, and the resonator 19 are also made of resin. Therefore, the above-mentioned intake duct 13, the first and second tubular members 15, 1.
6 and the resonator 19 are fixed by appropriate means such as adhesive, screwing, clinching, welding, etc.

The actuator 20 can be electrically easily controlled in rotation;
(4) Based on the rotation signal from internal combustion engine rotation detection (not shown), the control computer 22 controls the opening/closing plate fixed to the shaft 21 in synchronization with the engine rotation. 17 is rotated using the inner wall of the resonance chamber as a guide.

Next, details of the opening/closing plate 17 are shown in FIG.

lal in FIG. 3 is a front view of the opening/closing plate 17, and fbl is (al
It is an AA sectional view of. The opening/closing plate 17 has @1°2.
Three communicating holes 17a, 17b, and 17c are formed, respectively, and a hole 17d for fixing the shaft 21 of the actuator 2o is provided in the center. First and second communication holes 17a
, 17b has a diameter of Dl, and the third communication hole 17C has a diameter of D2.
The first communication hole 17a and the third communication hole 17C have the same diameter and face each other with respect to the center of the opening/closing plate 17.

The second communicating hole 17b is located on a diametrical straight line that is perpendicular to the diametrical straight line where the first and third communicating holes 17a and 17c are located. The center distance between the first communication hole 17a and the third communication hole 17c is equal to the distance between the centers of the first tubular member 15 and the second tube (5) member 16, and
The distance between the center of b and the center of the opening/closing plate 17 is equal to the distance between the center of the first communicating hole 17a and the center of the opening/closing plate 17. Further, the shaft 21 is screwed into the fixing hole 17d,
The opening/closing plate 17 is fixed by tightening or the like, and the maximum diameter of the opening/closing plate 17 is such that it can rotate without contacting the inner wall of the resonance chamber 18.

Next, the operation of this embodiment will be described.

As shown in Fig. 2, the engine rotation speed is read from the internal combustion engine rotation signal (not shown, obtained from a distributor or crank pulley, etc.) by a control computer 22 using a microcomputer.
A drive signal is sent to the actuator 20 so as to obtain a resonant frequency that matches the dominant frequency component of the intake noise during each rotation, and the opening/closing plate 17 is rotated to switch the resonant frequency. A flowchart showing the control method of the control computer 22 is shown in FIG. 4. The actuator 20 is rotated forward and backward even when the rotational speed of the internal combustion engine increases or decreases, and always synchronizes with the rotational speed to generate the resonance frequency (6 ) You can switch the number.

In addition, as a method of synchronizing the rotation speed of the machine 1, as shown in Fig. 5, three resonance frequencies f1oiv, rmid
, f up is synchronized stepwise with respect to the engine speed.

Next, details of the resonant frequency switching method of this embodiment will be explained with reference to FIGS. 6, 7, and 8. As shown in FIG. 6, the required lower limit resonance frequency f low is determined by the opening diameter DI ( >D2
) is made non-communicating, and the second tubular member 15 with an opening diameter D2 is made non-communicating.
The tubular member 16 can communicate with each other through the second communication hole 17b of the opening/closing plate 17. Resonant frequency f = obtained at this time
f low is Flow-(C/2g)・ycD22/4 (
■・eP) (1p = 1 + 0.8 D 2 ).

Next, the opening/closing plate 17 is rotated 180 degrees clockwise from the state where the lower limit resonance frequency is obtained (the state shown in FIG. 6) as shown in FIG.
By rotating, opening/closing (7) The second communicating hole 17b of the plate 17 comes to the position of the first tubular member 15 with the opening diameter DI, so the first tubular member 15 communicates with the opening of the second tubular member 16. The section is closed by an opening/closing plate 17. The intermediate resonance frequency obtained at this time f = f mid
is f mid = (C/2π)・πD12/4(V
・A'p) (7!p=p+0.8DI).

Furthermore, as shown in FIG. 8, rotate the opening/closing plate 17 clockwise 90
When rotated, the first and second tubular members 15 and 16 can communicate with each other simultaneously through the first communication hole 17a and the third communication hole 17c of the opening/closing plate 17. The upper limit resonance frequency f = f up obtained at this time is fup = (C/2yr) ・
(πDL 2+πD22)/4 (v-1p) βp = (4+ 0.8・, /-7□DI2+D22
)/4.

Next, a specific resonance frequency is calculated based on Fig. 6.7.8. For example, the volume of the resonance chamber 18 is V-1400cc,
, the length of the first and second tubular members 15.16 8) 7! =20++*, opening diameter DI-2 of the first tubular member 15
0-■, the opening diameter D2 of the second tubular member 16 is 1211, the lower limit resonance frequency flow is 8911Z, the intermediate resonance frequency fmid is +35117, the upper limit resonance frequency fup is 15211Z, and the actuator rotates the opening/closing plate. By sliding, the resonance frequency can be increased to 89
1(Z,,) 35H7, 15211Z can be switched.

In this example, the volume of the resonance chamber is V-1400cc, the length of the two tubular members #=20m, the opening diameter r)1=20III, D
2=12 mm, but by appropriately selecting these parameters, it is possible to switch to a desired resonance frequency for the same amount of rotation of the actuator.

As described above, in the resonator of this embodiment, two tubular members having different opening cross-sectional areas of the resonator are switched in synchronization with the engine speed using the opening/closing plate 17 directly connected to the actuator 20.
The resonant frequency is switched, and it is possible to obtain a plurality of frequencies at which a damping effect can be obtained, instead of a single frequency in the past. Further, since only three control steps are required for the actuator 20 that controls the opening/closing plate 17 (9), there is an advantage that the capacity of the control computer is small.

FIG. 9 shows the effect of applying the present invention to internal combustion engine intake noise reduction. The thin line (A) in the figure is the intake noise when no resonator is installed, and there is one noise peak at 2700 rpm, and an additional 4 noise peaks at 2700 rpm.
There is a large noise peak around 4,900 rpm from 000 rpm, which is a problem. This noise peak is caused by the second component of the engine speed, namely 90 Hz and 13311Z to 16
08Z is dominant. Therefore, the resonant frequencies of the resonator in this example are set to 89H2, 13511Z, and 15211Z, and the engine speeds are 2670 rpm, 4050 rpm, and 45 rpm.
By synchronously changing at 60 rotations, the thick line in the figure (
As shown in (c), conventional resonator installation (dotted chain line (
b)) It is possible to significantly reduce intake noise.

Next, other embodiments of the present invention will be described.

In the first embodiment described above, the resonator 19 was installed in the intake system and used as a method for reducing intake noise, but a resonator with the same (10) configuration was installed in the exhaust system to reduce exhaust noise. Similar effects can be achieved even when implemented as a device.

Further, in the first embodiment, the actuator 20 is mounted on the resonator, but it may be mounted on the intake duct 13 side as shown in FIG. 10. Furthermore, as shown in FIG. 11, the resonator mounting part is separated from the intake duct 13 in consideration of its ease of installation.
It is also possible to make it possible to change the mounting position freely.

In addition, in the first embodiment, one actuator is used to open and close the first and second tubular members 15 and 16 with different opening diameters.
As shown in Figure 12, the switching control was carried out by
By using two linear actuators 20a, 20b, it is also possible to easily control the communication combination of two tubular members. In this way, the opening/closing plate 17 can be used to open or close the first and second tubular members 15 and 16.
Since only OFF control is required, there are two control steps for the actuator 20, and the capacity of the control computer can be small.

Furthermore, as shown in FIGS. 13 and 14, two resonance frequencies can be obtained by simply controlling the opening and closing of any one of the two tubular members using only one linear actuator 20.

Further, in the first embodiment, the opening cross-sectional areas of the first and second tubular members 15 and 16 are different, but they may be the same, or (as shown in FIGS. 12, 13, and 14) (Example not shown) The lengths of the first and second tubular members 15 and 16 may be different.

It is also well known that if the natural resonance frequency of the intake passage pipe for intake air in the intake system matches the number of opening/closing signals of the intake valve, a large amount of mixed gas (fuel and intake air) will be sucked into the cylinder. The length of the intake pipe is selected to achieve resonance at a certain rotational speed of the internal combustion engine, increasing the engine output at that rotational speed.

Therefore, by installing the resonator of the above-mentioned embodiment in the middle of the intake pipe and making its resonance frequency variable, the natural resonance frequency of the entire intake pipe can be changed, and the opening/closing timing of the intake valve can be changed. It can also be implemented as a means to increase the output in the entire rotation range of the internal combustion engine by synchronizing with the internal combustion engine.

As explained above, in the resonator of the present invention, the cross-sectional area of the opening of the tubular member of the resonator is variably controlled in accordance with the rotational speed of the engine, so that the resonant frequency can be obtained in accordance with the operation of the engine. Furthermore, since the control steps of the actuator can be reduced, the capacity of the control computer can be reduced, which is an excellent effect.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional resonator, Figs. 2 and 3 show an embodiment of the present invention, Fig. 2 is a sectional view, and Fig. 3 is a fa.
t is a plan view of the opening/closing plate, and fbl in Fig. 3 is (A-A in al.
4 is a control flowchart, FIG. 5 is a characteristic diagram showing the relationship between engine speed and resonance frequency, and FIGS. 6, 7, and 8 show the relationship between the opening/closing plate and the tubular member. The figure shown,
FIG. 9 is a diagram for explaining the effects of the embodiment, and FIGS. 10, 11, 12, 13, and 14 are sectional views showing other embodiments. 15... first tubular member, 16... second tubular member, 1
(13) 7... Opening/closing plate, 18... Resonance chamber, 20... Actuator, 22... Control computer. Representative Patent Attorney Takashi Okabe (14) Ryoshiki Ginbaru Heat Protection l; υ-ノ

Claims (2)

[Claims] (1) A resonator consisting of a plurality of tubular members each having one end open to a gas flow path, a closed space communicating with the other end of the plurality of tubular members, and an opening/closing plate that blocks or communicates with the tubular members. A resonator comprising: an actuator that causes the opening/closing plate to open and close the tubular member based on an electric signal; and a control computer that controls an electric signal output to the actuator. (2) The resonator according to claim 1, wherein the plurality of tubular members have different opening cross-sectional areas.